KR20090089820A - Exposure apparatus and device manufacturing method - Google Patents

Abstract

An exposure apparatus and a method for manufacturing a device are provided to control the exposure and the position determination of a substrate by projecting an original pattern on the substrate using a projection optical system. An original pattern is projected on a substrate using a projection optical system(9). Substrate stages(6a,6b) are comprised in order to maintain substrates(5a,5b). A first detector detects the positions of marks(11a,11b) on the substrate. A controller controls the position determination and the exposure of the substrate. The controller controls the first detector to detect the position while moving the substrate stage. A second detector detects the surface position of the substrate.

Description

Exposure apparatus and device manufacturing method {EXPOSURE APPARATUS AND DEVICE MANUFACTURING METHOD}

This invention relates to the exposure apparatus which exposes a board | substrate by projecting the pattern of an original plate onto a board | substrate using a projection optical system, and the method of manufacturing a device using an exposure apparatus.

In recent years, the precision of the exposure apparatus used in lithography for manufacturing these devices, with the development of fine patterning and increasing the packing density, for example in semiconductor integrated circuit devices and liquid crystal panel devices. And improvements in function are underway. In particular, it is anticipated that techniques for positioning discs (also referred to as masks or reticles) and substrates (eg, wafers or glass plates) in nanometers for alignment are available.

The exposure apparatus sequentially transfers the pattern of the original plate to a plurality of shot regions on the substrate while moving the substrate in step units. An exposure apparatus that performs such transfer while the master and the substrate are stopped is called a stepper. An exposure apparatus that performs such transfer while scanning the original and the substrate is called a scanner or scanning stepper.

Recently, an exposure apparatus equipped with two substrate stages has been provided to satisfy two requirements, namely, improvement in overlay accuracy and throughput. Such an exposure apparatus includes an exposure station for exposing a substrate and a measurement station for measuring the substrate. While the exposure apparatus exposes the substrate at the exposure station, the substrate to be exposed next is measured at the measurement station. This makes it possible to improve the throughput while securing the measurement time of the substrate in order to improve the overlapping accuracy (Japanese Patent Laid-Open No. 2006-108582).

Global alignment schemes are available as substrate positioning methods. 10 is a diagram showing an arrangement of shot regions on the substrate 5. As shown in FIG. 10, a plurality of shot regions ST formed by preprocessing are arranged on the substrate 5. All shot regions are generally formed with the same patterns. Also, alignment marks are arranged in all shot regions. The substrate can be positioned by selecting shot regions (measured shot regions) for measuring positions of alignment marks from all such shot regions, and measuring positions of alignment marks of selected shot regions.

11 is a diagram illustrating metrology shot regions. For example, in FIG. 11, the positions of alignment marks of hatched metrology shots MS are measured. The arrangement information of the shot regions on the substrate can be obtained by statistically calculating the measurement value of each alignment mark. When measuring the position of the alignment mark, the alignment mark is moved to the field of view of the detection system and stopped at this field of view. This operation is performed, for example, by selecting alignment marks in the order indicated by the arrows in FIG. The arrow in FIG. 11 schematically shows the state in which the field of view of the detection system moves with respect to the substrate. In practice, since the field of view of the detection system is fixed, the substrate, i.e. alignment marks, move in the opposite direction to those indicated by the arrows with respect to the field of view of the detection system.

12 is a flowchart showing a sequence of substrate positioning (alignment) measurement (alignment measurement). Step S401 is a coarse alignment process, which roughly measures the arrangement of shot regions. In the outline alignment process, fewer shot regions are used as measurement objects (described later) than those used in the alignment mark imaging process and the alignment mark position calculation process (described below). Further, in the schematic alignment process, alignment marks are imaged by the detection system having a field of view wider than that of the detection system used in the alignment mark imaging process, and their positions are measured. In the schematic alignment process, for example, alignment marks of two shot regions are detected.

In the following steps, the substrate stage is driven based on the positions of the alignment marks measured in the schematic alignment process. Step S402 is a step driving process. In this process, the substrate stage is driven so that the alignment marks enter the field of view of the detection system based on the measurement result obtained in the schematic alignment process, and remain stationary in this field of view. Step S403 is an alignment mark imaging process. In this process, the detection system picks up the alignment mark images. Step S404 is an alignment mark position calculation process. In this process, the positions of the alignment marks are accurately detected based on the imaged alignment mark images. Steps S402 to S404 are repeated until it is determined in step S405 that the alignment marks of all the measurement shot regions have been measured, and the measurement process ends.

The global alignment method is excellent because high throughput and high precision can be obtained. Moreover, the global alignment method is convenient because it allows alignment according to the same correction method over the entire substrate area (Japanese Patent Laid-Open No. 09-218714).

In recent years, since the demand for alignment precision has become more stringent, conventionally, the amount of the amount is so small that error components that are not a problem cannot be ignored. Under these circumstances, for example, a proposal to improve alignment accuracy by measuring not only the position of the shot region but also its shape by measuring a plurality of alignment marks in the measurement shot region, and correcting the shape of the shot region to which the pattern is transferred is proposed. consist of. In this case, in order to calculate the shape of the shot region, it is advantageous in terms of precision to measure alignment marks on a plurality of scribe lines arranged around the shot region.

For example, a case where a shot magnification representing the shape of the shot region is calculated will be considered. Assuming that (eg, two) alignment marks disposed on one scribe line are measured, the shot magnification can be calculated along the direction of the scribe line, but cannot be calculated in a direction perpendicular to the scribe line. . This requires, for example, to use a method of estimating the shot magnification in the direction perpendicular to the scribe line from the direction along the scribe line. Conversely, if alignment marks on scribe lines in two orthogonal directions are measured, shot magnification in these two directions can be calculated.

Unfortunately, increasing the number of alignment marks to be measured, in turn, increases the number of drive operations of the substrate stage required for alignment mark measurement and the number of times it must remain stationary in the field of view of the detection system. Therefore, the resultant measurement processing time may adversely affect the overall throughput in the exposure apparatus mounting the two substrate stages as described above.

An exemplary object of the present invention is to provide an advantageous technique for suppressing an increase in the time required for measurement even when the number of measurement is increased.

According to a first aspect of the present invention, an exposure apparatus for exposing the substrate by projecting a pattern of the original onto a substrate using a projection optical system, comprising: a substrate stage configured to hold the substrate; A first detector configured to detect positions of marks on the substrate in a first direction and a second direction orthogonal to each other in a plane perpendicular to the optical axis direction of the projection optical system; And controlling the first detector to detect a position of a mark on the substrate while moving the substrate stage substantially in the first direction, and marking the mark on the substrate while moving the substrate stage substantially in the second direction. An exposure apparatus is provided that includes a controller configured to control exposure and positioning of the substrate based on detection results obtained by the first detector by controlling the first detector to detect a position of.

According to a second aspect of the present invention, there is provided an exposure apparatus for exposing a substrate by projecting a pattern of an original onto a substrate using a projection optical system, comprising: a substrate stage configured to hold the substrate; A first detector configured to detect positions of marks on the substrate in a first direction and a second direction orthogonal to each other in a plane perpendicular to the optical axis direction of the projection optical system; A second detector configured to detect a surface position of the substrate in the optical axis direction; And controlling the second detector to perform position detection while moving the substrate stage holding the substrate on a plane perpendicular to the optical axis, and based on the detection result obtained by the second detector in the optical axis direction. To control the positioning and exposure of the substrate based on the detection results obtained by the first detector and the second detector by controlling the first detector to perform position detection while controlling the surface position of the substrate. An exposure apparatus is provided that includes a configured controller.

According to a third aspect of the invention, there is provided a method of exposing a substrate using the above-described exposure apparatus; And developing the substrate.

Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

[First Embodiment]

2 is a diagram showing a schematic configuration of an exposure apparatus according to a preferred embodiment of the present invention. The exposure apparatus EX according to a preferred embodiment of the present invention comprises a measurement station 1 and an exposure station 2. Note that the exposure apparatus EX described herein is only one embodiment, and the present invention also applies to an exposure apparatus in which the measurement station 1 and the exposure station 2 are integrated. In addition, a scanning exposure apparatus for exposing while scanning a substrate will be exemplified as the exposure apparatus EX, but the exposure apparatus according to the present invention may be an exposure apparatus (stepper) for exposing while the substrate is stopped.

The exposure station 2 includes a disc stage (reticle stage) 4 holding a disc (reticle), an illumination optical system 8 for illuminating the disc 3 with exposure light, and a disc 3 illuminated with exposure light. And a projection optical system 9 for projecting the pattern onto the substrates (wafers) 5, i.e. 5a and 5b.

The exposure apparatus EX comprises two substrate stages (wafer stages) 6, ie 6a and 6b, which can move between the two stations 1 and 2. The substrate stages 6, ie 6a and 6b, are supported by a stage surface plate 7. The substrate (first substrate) held by one substrate stage is exposed at the exposure station 2, and the substrate (second substrate) held by the other substrate stage is measured at the measurement station 1. When the exposure of the first substrate and the measurement of the second substrate are finished, the positions of the two substrate stages are swapped so that the measured second substrate is conveyed to the exposure station 2, and the exposed first substrate carries out the next process. It is conveyed to the device (usually a developing device) for the purpose. Then, instead of the first substrate, a new substrate (third substrate) provided to the substrate stage is measured at the measurement station 1. The exposure apparatus EX simultaneously performs measurement and exposure in the manner described above. The number of substrate stages may be one or more than three.

In this specification, the direction parallel to the optical axis of the projection optical system 9 is defined as the Z direction, and two orthogonal directions in the plane perpendicular to the Z direction are defined as the X and Y directions. In other words, the direction is defined in this specification based on the XYZ coordinate system. For convenience, the scanning directions of the original plate 3 and the substrate 5 are assumed to be Y directions. In addition, the rotation directions about the X-axis, Y-axis, and Z-axis are respectively θ X, θ Y, and θ Z. Assume the directions. The first and second directions described in the scope of the claims may be interpreted as the X and Y directions, respectively, or may be interpreted as the Y and X directions, respectively.

The disc 3 is illuminated with exposure light having a uniform illuminance distribution by the illumination optical system 8. The exposure light emitted from the illumination optics 8 may be, for example, light emitted by a mercury lamp, KrF excimer laser, ArF excimer laser, F ₂ laser, or Extreme Ultra Violet (EUV) light source. However, exposure light is not specifically limited to these.

Original stage (4) that is the plane, perpendicular to the optical axis of the projection optical system (9), can be moved two-dimensionally on the XY plane, θ Z It can rotate finely in the direction. The disc stage 4 is driven by a disc stage drive mechanism (not shown) such as a linear motor. A mirror is disposed on the disc stage 4 for measuring the position of the disc stage 4 by a laser interferometer (not shown). The position of the disc stage 4 (as a result, the disc 3) on the XY plane and its rotation angle θ Z are measured in real time by the laser interferometer, and the measurement results are transmitted to the controller CNT. The controller CNT controls the disc stage driving mechanism based on the measurement results obtained by the laser interferometer to position the disc 3.

The projection optical system 9 projects the pattern of the original plate 3 on the substrate 5 at a predetermined projection magnification β . In this operation, the substrate 5 is exposed. The projection optical system 9 typically comprises a plurality of optical elements supported by a metallic optical system barrel. The projection magnification β of the projection optical system 9 may be set to 1/4 or 1/5, for example.

The substrate stage 6 may include a Z stage including a substrate chuk holding the substrate 5, an X-Y stage supporting the Z stage, and a base supporting the X-Y stage. The substrate stage 6 is driven by a substrate stage driving mechanism (not shown) such as a linear motor. The substrate stage drive mechanism is controlled by the controller CNT.

A mirror is placed on the substrate stage 6 to measure the position of the substrate stage 6 using a laser interferometer (not shown). The position of the substrate stage 6 (as a result, the substrate 5) and its rotation angle θ Z on the XY plane are measured in real time using a laser interferometer, and the measurement results are transmitted to the controller CNT. Similarly, the position of the substrate stage 6 in the Z direction and its rotation angles θ X And θ Y are measured in real time using a laser interferometer, and the measurement results are sent to the controller CNT. The controller CNT controls the substrate stage driving mechanism based on the measurement results obtained by the laser interferometer, so that the position of the substrate 5 and its rotation angles θ X, θ Y in the X, Y, and Z directions , And θ Z.

The disc alignment detection system is arranged in the vicinity of the disc stage 4. The disc alignment detection system includes the substrate stage reference marks 11 (ie, 11a and 11b) on the substrate stages 6 through the disc stage reference mark 10 and the projection optical system 9 set on the disc stage 4. Is detected. The disc alignment detection system enables the alignment of the substrate stage reference marks 11 with respect to the disc stage reference mark 10.

The measurement station 1 includes an alignment detection system (first detector) for detecting positions of the substrate 5 and the substrate stage reference mark 11, and surface position information (position information and tilt in the Z direction) of the substrate 5. And a focus detector (second detector) for detecting information). The focus detection system 12 includes a projection system that projects detection light onto the surface of the substrate 5, and a light reception system that receives light reflected by the substrate 5. The detection result (measurement value) obtained by the focus detection system 12 is transmitted to the controller CNT. The controller CNT drives the Z stage based on the detection result obtained by the focus detection system 12, and adjusts the position (focus position) and the inclination angle in the Z direction of the substrate 5 held by the Z stage. The position detection results (measurement values) of the substrate 5 and the substrate stage reference mark 11, obtained by the alignment detection system 13, are transmitted to the controller CNT as parts of the positioning information.

The substrate stage reference mark 11 is set to almost the same height as the surface of the substrate 5 and is used for position detection by the disc alignment detection system and the alignment detection system 13. In addition, since the substrate stage reference mark 11 has a flat surface portion, it functions as a reference plane of the focus detection system 12. The substrate stage reference marks 11 can be set at a plurality of corners of the substrate stage 6.

As shown in FIG. 4, the substrate 5 includes a plurality of alignment marks (hereinafter also referred to simply as marks) AM1 to AM8, in which positions are detected by the alignment detection system 13. A plurality of alignment marks in this role are arranged around respective shot regions on the substrate 5, and the positional relationship between the alignment marks and the shot region in the X and Y directions is well known. Thus, the position of the shot region can be detected by detecting the positions of the alignment marks.

The operation of the exposure apparatus EX will be described below. After the substrate 5 is loaded into the measurement station 1, the substrate stage reference mark 11 is detected by the alignment detection system 13. To implement this operation, the controller CNT moves the X-Y stage while monitoring the output from the laser interferometer, allowing the substrate stage reference mark 11 to enter the field of view of the alignment detection system 13. In this operation, the alignment detection system 13 detects the positional information of the substrate stage reference mark 11 on the coordinate system defined by the laser interferometer. In the measurement station 1, the focus detection system 12 detects surface position information of the substrate stage reference mark 11.

The positions of the plurality of shot regions defined on the substrate 5 are detected. The controller CNT moves the XY stage while monitoring the output from the laser interferometer so that alignment marks disposed around the scribe line of each shot region on the substrate 5 pass through the field of view of the alignment detection system 13. do. During the movement process, the alignment detection system 13 detects the positions of the plurality of alignment marks formed around the shot area on the substrate 5. This operation is repeated for a plurality of scribe lines extending along the X and Y directions, thereby detecting the selected alignment marks. In this operation, the positions of the respective alignment marks on the coordinate system defined by the laser interferometer are detected. Details of the alignment mark measurement will be described later.

Based on the substrate stage reference mark 11 obtained by the alignment detection system 13 and the detection results of each alignment mark, the positional relationship between the substrate stage reference mark 11 and each alignment mark is obtained. Since the positional relationship between each alignment mark and each shot region is well known, the positional relationship between the substrate stage reference mark 11 in the X-Y plane and each shot region on the substrate 5 can also be determined.

The focus detector 12 detects portions of the surface position information of the substrate 5 in all shot regions on the substrate 5. The detection results are associated with positions in the X and Y directions on the coordinate system defined by the laser interferometer and stored in the controller CNT.

The substrate stage reference plate 14 is based on the surface position information of the substrate stage reference mark 11 obtained by the focus detection system 12 and the detection results of the surface position information on each shot region of the substrate 5. The positional relationship between the surfaces of and each shot region is determined.

The substrate is exposed at the exposure station 2 based on the measurement results of the substrate 5 obtained at the measurement station 1.

The controller CNT moves the X-Y stage, causing the substrate stage reference mark 11 to enter the field of view of the disc alignment detection system. The disc alignment detection system detects the substrate stage reference mark 11 through the disc stage reference mark 10 and the projection optical system 9. That is, the positional relationship between the disc stage reference mark 10 and the substrate stage reference mark 11 in the X and Y directions, and the positional relationship in the Z direction is detected through the projection optical system 9. In this operation, the image position of the original pattern projected on the substrate by the projection optical system 9 is detected using the substrate stage reference mark 11.

When the image position of the original pattern formed by the projection optical system 9 is detected, the controller CNT moves the X-Y stage to expose each shot region on the substrate 5. Using the measurement results obtained at the metrology station 1, each shot area is scanned and exposed. In the exposure of each shot region, the controller CNT includes information obtained at the measurement station 1 (positional relationship between the substrate stage reference mark 11 and each shot region) and information obtained at the exposure station 2. Based on the positional relationship between the substrate stage reference mark 11 and the image of the original pattern, the alignment between the shot plate 3 and each shot region on the substrate 5 is controlled.

The controller CNT also controls the surface position of the substrate 5 such that during the scanning exposure, the surface of the substrate 5 is aligned with the image plane of the projection optical system 9. This control is based on the positional relationship between the surface of the substrate stage reference mark 11 and the surface of the substrate 5, obtained at the metrology station 1, and the substrate stage reference mark 11, obtained at the exposure station 2. It is performed based on the positional relationship between the surface of and the upper surface of the original pattern formed by the projection optical system 9.

Next, the alignment mark measurement according to the present embodiment will be described in detail. 3 is a diagram schematically showing an alignment mark measurement method. 4 is a diagram schematically showing the visual field AF of the shot region ST on the substrate 5, the alignment marks AM1 to AM8, and the alignment detection system 13 during the movement of the substrate stage 6. As described above, a plurality of shot regions ST are disposed on the substrate 5, and alignment marks are disposed at the periphery (scribe line) of each shot region.

In this embodiment, the alignment detection system 13 detects the positions of the plurality of alignment marks while moving the substrate stage 6 parallel to the X and Y directions in the arrangement of the shot regions. Note that the alignment detection system 13 includes an image sensor. The image sensor detects the positions of the alignment marks in the field of view of the alignment detection system 13 by imaging the alignment marks and processing the obtained image.

For example, the alignment marks are disposed on the scribe lines along the scribe lines almost in the X direction (marks in FIG. 4, AM5, AM6, AM7, and AM8) and on the scribe lines along the nearly Y direction. Group of marks (marks in Fig. 4, AM1, AM2, AM3, and AM4). In practice, “almost” is used herein in view of the fact that the directions of the scribe lines may not be exactly parallel to the X or Y direction due to the deformation of the shot area or its arrangement.

For convenience, the former may be referred to as the first mark group and the latter may be referred to as the second mark group. In addition, the X direction may be referred to as the first direction, and the Y direction may be referred to as the second direction. Under this definition, the controller CNT controls the alignment detection system (first detector) 13 while moving the substrate stage 6 along the almost first direction to detect the first mark group. The controller CNT also controls the alignment detection system 13 while moving the substrate stage 6 along the nearly second direction to detect the position of each mark in the second mark group. The controller CNT changes the position of the substrate stage 6 in the second direction and detects the position by controlling the alignment detection system 13 while moving the substrate stage 6 along the almost first direction for every change in the position. Run The controller CNT also changes the position of the substrate stage 6 in the first direction and controls the alignment detection system 13 while moving the substrate stage 6 along a nearly second direction for every change in its position. To perform position detection.

The above-described measurement method may detect positions of a plurality of alignment marks corresponding to a plurality of shot regions (for example, all shot regions in contact with the scribe line) while moving the substrate stage 6. .

Note that the arrows in FIGS. 3 and 4 schematically show the state in which the field of view of the alignment detection system 13 moves relative to the substrate. In practice, since the alignment detection system 13 is fixed in position, the substrate, i.e., alignment marks, move in directions opposite to the directions indicated by the arrows.

In order to meet the need to improve alignment accuracy, it is necessary to increase the number of metrology alignment marks in each metrology shot as well as the number of metrology shot regions. For this reason, it is desirable to measure alignment marks on a plurality of scribe lines as well as alignment marks on one scribe line. Measuring alignment marks on scribe lines in the same direction is insufficient to calculate the shape of each shot region. For example, when only the alignment marks on the scribe line are measured along the Y direction in FIG. 3, only the alignment marks AM1 and AM2 in FIG. 4 (when two scribe lines are measured along the Y direction, the alignment Only marks AM1 to AM4 can be measured. In this case, it is impossible to measure the change in the shape of each shot region along the X direction. Therefore, it is desirable to measure alignment marks disposed on the scribe lines along both the X and Y directions.

This not only measures a plurality of alignment marks but also measures the two-dimensional shape of each shot region, thereby making it possible to correct the position and shape of each shot region and perform exposure.

3 illustrates a case where alignment marks are measured on scribe lines every other row and every other row, but this is only one example. The scribe lines to measure can be determined according to the alignment accuracy required. If there is a portion that requires higher precision, such as shot regions around the periphery of the substrate, the density of the scribe lines to measure can vary with location. Also, the position and number of alignment marks are not limited to those shown in FIG.

1 is a flowchart showing a sequence of alignment mark measurement. This sequence is controlled by the controller CNT. First, step S101 is a schematic alignment process for roughly measuring the arrangement of shot regions. The schematic alignment process is the same as in step S401 of FIG.

In step S102, the controller CNT starts the driving of the substrate stage 6 according to the target drive path in which the alignment marks on the scribe line pass through the field of view of the alignment detection system 13. More specifically, the substrate stage 6 moves the field of view of the alignment detection system 13 in the directions indicated by the arrows in FIG. 3 (the substrate stage 6 is opposite the directions indicated by the arrows). To be moved).

In step S103, the controller CNT calculates the position of the substrate stage 6 at the moment when the alignment detection system 13 picks up the alignment mark. More specifically, the controller CNT is based on the shot arrangement positions measured in the schematic alignment process and the design positions of the alignment marks corresponding to the preset shot area, so that the moment of the alignment mark entering the field of view of the alignment detection system 13 is determined. The position of the substrate stage 6 is calculated.

The position of the substrate stage 6 (substrate 5) in the Z direction while the substrate stage 6 moves along the X-Y plane will be described herein. When the alignment mark is picked up by the alignment detection system 13, the alignment mark needs to be aligned with the object plane (focus position) of the alignment monk detection system 13. When the alignment mark is not aligned with the object plane, the contrast of the image obtained by imaging the alignment mark is reduced, causing a decrease in measurement accuracy. In order to avoid such a situation, in this embodiment, when the alignment mark is aligned with the object plane of the alignment detection system 13, the measurement value obtained by the focus detection system 12 is stored. During the drive of the substrate stage 6, the focus detection system 12 measures the surface position of the substrate 5 in the Z direction, and the position of the substrate stage 6 in the Z direction is always the focus detection system 12. The measured values obtained by) are controlled to match those previously stored. This makes it possible to align the alignment mark with the object plane of the alignment detection system 13 during the drive of the substrate stage 6.

In step S104, the controller CNT waits until the substrate stage 6 reaches the imaging position calculated in step S103, and then controls the alignment detection system 13 to pick up the alignment mark. The controller CNT stores the position of the substrate stage 6 at the time of imaging the alignment mark.

In step S105, the controller CNT calculates the position of the alignment mark in the field of view of the alignment detection system 13 using a known method based on the image of the alignment mark image picked up. Next, the controller CNT calculates the position of the alignment mark on the substrate 5 based on the position of the substrate stage 6 when imaging the alignment mark and the position of the alignment mark in the field of view of the alignment detection system 13. . The case where the position of the alignment mark in the visual field of the alignment detection system 13 is computed immediately after imaging the alignment mark was demonstrated as an example in this specification. However, the position of the alignment mark can be calculated after imaging all the alignment marks and after the captured data is stored.

The processing in steps S103 to S105 is repeated until it is determined in step S106 that all of the alignment marks measured on one scribe line have been measured.

If it is determined in step S106 that all the alignment marks measured on one scribe line have been measured, the controller CNT ends the scan drive of the substrate stage 6 in step S107. By the processing described above in steps S102 to S107, alignment marks disposed on one scribe line were measured.

Subsequently, the processing in steps S102 to S107 is executed for the alignment marks disposed on the other scribe lines until it is determined in step S108 that the alignment marks on all the scribe lines have been measured.

According to this embodiment, alignment marks on the scribe line are measured along the X and Y directions while moving the substrate stage. This makes it possible to improve the measurement accuracy while reducing the time taken for the measurement process.

Second Embodiment

In the second embodiment, the focus detection system (second detector) 12 is parallel to the position detection by the alignment detection system (first detector) 13 in the optical axis direction (Z direction) of the projection optical system 9. The surface position of the board | substrate 5 is detected. In the present specification, when one operation and another operation are executed in parallel, at least a portion of a period of one operation overlaps at least a portion of a period of another operation.

Details not specifically mentioned as the configuration and operation of the exposure apparatus according to the second embodiment may be the same as in the first embodiment. In the following description, substrate surface position detection or metrology will be referred to as focus detection or metrology.

FIG. 5 is a diagram schematically illustrating a method of measuring positions of alignment marks and a surface position of a substrate. FIG. Alignment mark measurement and focus measurement are performed in parallel while moving the substrate stage 6 in the directions indicated by the thick arrows in FIG. 5. Only the alignment mark measurement is performed while moving the substrate stage 6 in the directions indicated by the thin arrows in FIG. 5. The focus detection system 12 is configured to be able to perform focus measurement only when the substrate stage 6 moves in the directions (Y direction) indicated by the thick arrows in FIG. 5. However, the focus detection system 12 may be configured to perform focus measurement both when the substrate stage 6 moves in the X direction and when it moves in the Y direction. In such a configuration, both alignment mark measurement and focus measurement can be performed in parallel when the substrate stage 6 moves in the X direction and in the Y direction.

By performing alignment mark measurement and focus measurement in parallel, it becomes possible to reduce the time required for measuring the substrate 5. Further, the alignment detection system 13 performs position detection while aligning the substrate surface position with the object surface of the alignment detection system 13 based on the detection result of the substrate surface position acquired by the focus detection system 12. It is possible.

5 schematically shows a state in which the field of view of the alignment detection system 13 and the field of view of the focus detection system 12 move relative to the substrate. In practice, since the alignment detection system 13 and the focus detection system 12 are fixed in position, the substrate moves in the direction opposite to the directions indicated by the arrows.

6 is a diagram schematically showing the fields of view of the alignment detection system 13 and the focus detection system 12. As schematically shown in FIG. 6, the center of view of the focus detection system 12 may be approximately the same as the center of view of the alignment detection system 13. In addition, as schematically shown in FIG. 6, when the scribe line passes the field of view AF of the alignment detection system 13, the focus detection system 12 having the field of view FF passes through the scribe line of the adjacent shot regions ST. Measure surface locations. Arrows in FIG. 6 indicate the substrate moving direction.

7 is a flowchart showing a sequence of alignment mark measurement. This sequence is controlled by the controller CNT. First, step S201 is a schematic alignment process that schematically measures the arrangement of shot regions. The schematic alignment process is the same as in step S401 of FIG.

In step S202, the controller CNT starts the driving of the substrate stage 6 according to the target drive path in which the alignment marks on the scribe line pass through the field of view of the alignment detection system 13. More specifically, the substrate stage 6 is moved so that the field of view of the alignment detection system 13 moves in the direction indicated by the arrow in FIG. 6 (the substrate stage 6 moves in the opposite direction as indicated by the arrow). Driven.

In step S203, the controller CNT determines whether the current drive of the substrate stage 6 is to perform only alignment measurement or to execute alignment measurement and focus measurement at the same time. If this drive is to perform only alignment measurement, the controller CNT repeats steps S204 to S207. Steps S204 to S207 are the same as the steps S103 to S106 described above.

If the current driving of the substrate stage 6 is to perform alignment measurement and focus measurement at the same time, the controller CNT executes the processing of steps S208, S204 'to S207', and S211. In step S208, the controller CNT controls the focus detection system 12 to start focus measurement. The processing of steps S208 'to S207' subsequent to step S208 is the same as those in steps S204 to S207. In step S211, the controller CNT waits until the substrate stage 6 reaches a position corresponding to the focus measurement end point on the current scribe line, and then ends the focus measurement.

It is determined in step S207 that the measurement is finished, or after step S211 is executed, the controller CNT finishes the scan drive of the substrate stage 6 in step S209. By the above-described processing from steps S202 to S209, the measurement of the alignment marks arranged on one scribe line and the focus measurement performed in parallel with it are terminated.

Subsequently, the above-described processing is repeated by changing the target scribe line to another scribe line until it is determined in step S210 that the alignment marks on all the scribe lines have been measured.

The exposure at the exposure station 2 positions each shot area based on the above-described results of the alignment mark measurement and the focus measurement at the measurement station 1, and the surface position of the shot area and the projection optical system 9 ) By aligning the top surface of the

According to this embodiment, alignment mark measurement and focus measurement are performed in parallel, thereby reducing the time required for substrate measurement.

Third Embodiment

The third embodiment provides an improved technique from the first or second embodiment. Details not specifically mentioned herein may be the same as in the first or second embodiment.

In the third embodiment, when the arrangement direction of the alignment marks deviates from the X and Y directions due to the deformation of the arrangement of the shot regions on the substrate 5, the controller CNT moves the substrate stage 6 based on the arrangement direction. Correct the direction. For example, the controller CNT is based on the positions of two or more alignment marks measured immediately before the alignment mark currently measured, and the difference between the moving direction (target drive path) of the substrate stage 6 and the arrangement direction of the shot regions. Is calculated and the moving direction (target drive path) of the substrate stage 6 is corrected based on the calculated difference.

8 schematically shows a state in which the controller CNT corrects the target drive path TP of the substrate stage 6 before measuring the next alignment mark based on the position measurement values of the two alignment marks AM1 and AM2. Drawing. The arrow in FIG. 8 schematically shows the state in which the field of view of the alignment detection system 13 moves with respect to the substrate. In reality, since the field of view of the alignment detection system 13 is fixed, the substrate, that is, the alignment marks move in the direction opposite to the direction indicated by the arrow with respect to the field of view of the alignment detection system.

Such correction of the target drive path can be performed in alignment mark measurement according to the first embodiment or in parallel processing of alignment mark measurement and focus measurement according to the second embodiment.

FIG. 9 is a flowchart showing a sequence of processing in the case where the target drive path correction function is added to the configuration according to the first embodiment. This processing is when step S300 is added between steps S105 and S106 in the sequence shown in FIG.

In step S306, the controller CNT is positioned on the alignment mark image (e.g., corresponding to alignment mark AM1 shown in Fig. 8) calculated in the immediately preceding step S105, and the alignment mark image (e.g., calculated in the previous step S305). On the basis of the position of the alignment mark AM2 shown in FIG. 8, the difference between the moving direction (target drive path TP) of the substrate stage 6 and the arrangement direction of the shot regions is calculated. If the difference between the moving direction and the arrangement direction of the shot regions exceeds the allowable value, the controller CNT corrects the moving direction (target drive path TP) of the substrate stage 6.

[Application Example]

The device manufacturing method according to a preferred embodiment of the present invention is suitable for the manufacture of devices (eg, semiconductor devices and liquid crystal devices). Such a method may include exposing the substrate coated with the photoresist to light using the above-described exposure apparatus, and developing the substrate exposed in the exposing step. In addition to the steps described above, the device manufacturing method may include other well known steps (eg, oxidation, deposition, evaporation, doping, planarization, etching, resist removal, dicing, bonding, and Packaging steps).

While the invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

1 is a flowchart showing a sequence of alignment mark mark measurement.

2 is a diagram showing a schematic configuration of an exposure apparatus according to a preferred embodiment of the present invention.

3 is a diagram schematically showing an alignment mark measurement method.

4 is a diagram illustrating an example of arrangement of alignment mark marks;

FIG. 5 is a schematic diagram illustrating a method of measuring positions of alignment marks and a surface position of a substrate. FIG.

6 is a diagram schematically showing the fields of view of the alignment detection system and the focus detection system.

7 is a flowchart showing a sequence of alignment mark measurement.

8 is a diagram schematically illustrating modification of a target drive path of a substrate stage.

9 is a flowchart showing a sequence of alignment mark measurement, including the function of correcting a target drive path.

10 is a schematic diagram showing an example of shot arrangement.

11 is a schematic diagram illustrating an example of metrology shots.

12 is a flowchart showing a sequence of alignment measurement.

<Explanation of symbols for the main parts of the drawings>

2: exposure station

3: disc

4: disc stage

5a: substrate

5b: substrate

6a: substrate stage

6b: substrate stage

7: Stage plate

8: illumination optical system

9: projection optical system

10: disc stage reference mark

11a: substrate stage reference mark

11b: substrate stage reference mark

12: focus detector

13: alignment detector

Claims (7)

An exposure apparatus for exposing the substrate by projecting a pattern of the original onto a substrate using a projection optical system, A substrate stage configured to hold the substrate; A first detector configured to detect positions of marks on the substrate in a first direction and a second direction orthogonal to each other in a plane perpendicular to the optical axis direction of the projection optical system; And Control the first detector to detect a position of a mark on the substrate while moving the substrate stage substantially along the first direction, and control the first detector to move the substrate stage substantially along the second direction. A controller configured to control the positioning and exposure of the substrate based on the detection results obtained by the first detector by controlling the first detector to detect a position Exposure apparatus comprising a. The method of claim 1, The controller controls the first detector to change the position of the substrate stage in the second direction and perform position detection while moving the substrate stage substantially along the first direction for every change in its position. And change the position of the substrate stage in the first direction, and control the first detector to perform position detection while moving the substrate stage substantially along the second direction for every change in the position. Exposure apparatus. The method of claim 1, A second detector configured to detect the surface position of the substrate in the optical axis direction while moving the substrate in parallel with the position detection by the first detector, And the controller controls the first detector to perform position detection while controlling the surface position of the substrate in the optical axis direction based on the detection result obtained by the second detector. The method of claim 3, The controller controls, upon exposure of the substrate, the position of the substrate in the first and second directions based on the detection results obtained by the first detector, and by the second detector. An exposure apparatus that controls the position of the substrate in the optical axis direction based on the obtained detection result. The method of claim 1, And the controller corrects the moving direction of the substrate stage based on the arrangement direction when the arrangement direction of the marks on the substrate deviates from the first direction and the second direction. An exposure apparatus for exposing the substrate by projecting a pattern of the original onto a substrate using a projection optical system, A substrate stage configured to hold the substrate; A first detector configured to detect positions of marks on the substrate in a first direction and a second direction orthogonal to each other in a plane perpendicular to the optical axis direction of the projection optical system; A second detector configured to detect a surface position of the substrate in the optical axis direction; And Controlling the second detector to perform position detection while moving the substrate stage holding the substrate on a plane perpendicular to the optical axis, and based on the detection result obtained by the second detector By controlling the first detector to perform position detection while controlling the surface position of the substrate, thereby controlling positioning and exposure of the substrate based on detection results obtained by the first detector and the second detector. Controller Exposure apparatus comprising a. As a device manufacturing method, Exposing the substrate using an exposure apparatus as defined in any one of claims 1 to 6; And Developing the substrate Device manufacturing method comprising a.

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